npgsql - Npgsql2: [#1011325] Escaped strings don't work with EF.

Log Message:
-----------

[#1011325] Escaped strings don't work with EF. Thanks  Andrey Polyakov for patch and tests.

Npgsql had a problem when hadling strings with escaped strings. This patch adds the proper syntax in order for this to
workcorrectly. Check https://github.com/franciscojunior/Npgsql2/pull/10 for more info about this fix. 

Modified Files:
--------------
    Npgsql2/src/Npgsql/SqlGenerators:
        VisitedExpression.cs (r1.19 -> r1.20)

(http://cvs.pgfoundry.org/cgi-bin/cvsweb.cgi/npgsql/Npgsql2/src/Npgsql/SqlGenerators/VisitedExpression.cs?r1=1.19&r2=1.20)